Review of Palaeobotany and Palynology, 66 (1990): 293-312 293 Elsevier SciencePublishers B.V., Amsterdam Early Cretaceous palynology of three boreholes from northern Western Desert (Egypt)* A.M. Omran, H.A. Soliman and M.S. Mahmoud Geology Department, Faculty of Science, Assiut University, Assiut, Egypt (Received December 1, 1989; revised and accepted March 1, 1990) g ABSTRACT Omran A.M., Soliman, H.A. and Mahmoud, M.S., 1990. Early Cretaceous palynology of three boreholes from northern Western Desert (Egypt). Rev. Palaeobot. Palynol., 66: 293-312. A palynologicalstudy has been carried out on Early Cretaceous ditch rock samples from three boreholes drilled in the northern Western Desert of Egypt. The palynomorph content was qualitativelyand quantitativelyanalysed with emphasis on dinoflagellatecysts and sporomorphs. The first provided the ages, necessaryfor correlation of the boreholes. Two successive sporomorph palynoflorasand three successivedinoflagellatecyst palynoflorascould be recognized in the Lower Cretaceous of the Western Desert. Furthermore, depositional environments were deduced resulting in identification of different paleoenvironmentalregions in the northern Western Desert. The palynologicalcompositionaldevelopmentis compared with contemporaneous successions from Europe, Atlantic, North Africa, Egypt and other parts of the Tethyan Realm. Introduction The majority of previous palynological investi- gations of the Egyptian Jurassic and/or Lower Cretaceous concentrated on sporomorphs. Import- ant palynological contributions have been made by Saad (1978), Sultan (1978, 1986 and 1987) and Schrank (1982, 1983 and 1987) amongst others. Stratigraphic studies on Egyptian Jurassic and Early Cretaceous dinoflagellate cysts (dinocysts) are still meagre and they focus only on restricted stratigraphic intervals (e.g. Schrank, 1987). In an attempt to accomplish a more comprehen- sive palynological study Mahmoud (1989) investi- gated the Middle Jurassic-Lower Cretaceous of three wells from the northern part of the Western Desert. Borehole locations are indicated in Fig.1. He qualitatively and quantitatively analysed the *Contribution to the I.G.C.P. projects no. 262 "Tethyan Cretaceous Correlation" and no. 245 "Nonmarine Cretaceous Correlations". sections for their pollen/spores and dinocyst content. Five dinocyst palynofloras and three spore/pollen palynofloras could be recognized in the ?Bajocian/Callovian-Albian. Results presented here form part of the afore- mentioned study. They focus on the Lower Cretaceous part of the three boreholes and aim to: (1) establish a palynostratigraphic framework for the northern Western Desert, based on both sporomorphs and dinocysts, (2) calibrate with Early Cretaceous Tethyan standard successions, (3) assess ages and compare with original assess- ments by drilling companies, (4) correlate the three wells, (5) define recognizable steps in the composi- tional development of the palynofloras, (6) infer depositional environments and (7) evaluate the regional significance of the obtained data. Geological setting Inferred from deep drilling, the sedimentary column of the Western Desert is thick (up to several kilometers) and includes successions from